In wire harness circuits used in automobiles, it is often required to make one or more branch circuits from a main circuit. To this end there have been often used the following two branching systems, i.e. a splice joint system and a joint connector system. In the splice joint system, a part of an electrically insulating sheath covering a main wire is pealed off and a branch circuit wire is connected to an exposed part of the main circuit by clamping. The joint connector system is described in the following Patent document 1. In this joint connector system, clamp terminals are connected to ends of a main circuit wire and a branch circuit wire and these clamp terminals are connected to each other by means of a common joint connector.
Patent document 1: Japanese Patent Kokai 2005-71614